Forest degradation and biomass damage resulting from logging is currently difficult to evaluate with satellite images, but contributes substantially to carbon emissions in the tropics. To address this situation, we mo...Forest degradation and biomass damage resulting from logging is currently difficult to evaluate with satellite images, but contributes substantially to carbon emissions in the tropics. To address this situation, we modelled how changes in the minimum felling diameter affect stem density, basal area and the related carbon biomass at the end of the felling cycle （30 years） in a semi-deciduous natural forest in Cameroon. With new MFDs estimates, at 7% logging damage rate, we found that the stem density of initially harvestable trees reduces from 12.3 （50.4 MgC·ha^-1） to 6.7 （32.5 MgC·ha^-1） trees per ha and the number of initial residual trees increases from 80 （18.9MgC·ha^-1） to 85.7 （36.8 MgC·ha^-1） trees per ha. This corresponds to an avoided damage estimated at 17.9 MgC·ha^-1. We also found that increasing mortality and damage intensity also increases the damage on carbon biomass estimated to be 8.9 MgC·ha^-1 at 10% or to be 17.4 MgC.hal at 15% logging damage. Overall, our study shows that proper determination of MFD of logged species taking into consideration their capacity of reconstitution and the Reduced Impact Logging can avoid the loss of up to 35 MgC·ha^-1.展开更多
A germination experiment of pre-treated seeds of Melia azedarach was conducted in the nursery of Forestry and Wood Technology Discipline,Khulna University,Bangladesh.Matured seeds of Melia azedarach were collected fro...A germination experiment of pre-treated seeds of Melia azedarach was conducted in the nursery of Forestry and Wood Technology Discipline,Khulna University,Bangladesh.Matured seeds of Melia azedarach were collected from healthy trees of National Botanical Garden,Bangladesh and were treated with five pre-sowing treatments（control,immersion in cold water,immersion in hot water,scarification with sand paper,and immersion in concentrated H2SO4） on seed germination.Results revealed that the germination rates of pre-sowing treated seeds were significantly increased compared to those in control,except for cold water treatment.The highest germination success（80%） was found in scarification with sand paper,followed by 74% and 69% in immersion in H2SO4 and hot water treatment,respectively.Germination started on 8-11 days and completed on 20-21 days of the germination period in all cases.Analysis of variance showed the significance difference in germination success among the treatments but no significance difference in germination period among the treatment.Hot water treatment may be recommended on seed germination of the species in rural Bangladesh.展开更多
文摘Forest degradation and biomass damage resulting from logging is currently difficult to evaluate with satellite images, but contributes substantially to carbon emissions in the tropics. To address this situation, we modelled how changes in the minimum felling diameter affect stem density, basal area and the related carbon biomass at the end of the felling cycle （30 years） in a semi-deciduous natural forest in Cameroon. With new MFDs estimates, at 7% logging damage rate, we found that the stem density of initially harvestable trees reduces from 12.3 （50.4 MgC·ha^-1） to 6.7 （32.5 MgC·ha^-1） trees per ha and the number of initial residual trees increases from 80 （18.9MgC·ha^-1） to 85.7 （36.8 MgC·ha^-1） trees per ha. This corresponds to an avoided damage estimated at 17.9 MgC·ha^-1. We also found that increasing mortality and damage intensity also increases the damage on carbon biomass estimated to be 8.9 MgC·ha^-1 at 10% or to be 17.4 MgC.hal at 15% logging damage. Overall, our study shows that proper determination of MFD of logged species taking into consideration their capacity of reconstitution and the Reduced Impact Logging can avoid the loss of up to 35 MgC·ha^-1.
文摘A germination experiment of pre-treated seeds of Melia azedarach was conducted in the nursery of Forestry and Wood Technology Discipline,Khulna University,Bangladesh.Matured seeds of Melia azedarach were collected from healthy trees of National Botanical Garden,Bangladesh and were treated with five pre-sowing treatments（control,immersion in cold water,immersion in hot water,scarification with sand paper,and immersion in concentrated H2SO4） on seed germination.Results revealed that the germination rates of pre-sowing treated seeds were significantly increased compared to those in control,except for cold water treatment.The highest germination success（80%） was found in scarification with sand paper,followed by 74% and 69% in immersion in H2SO4 and hot water treatment,respectively.Germination started on 8-11 days and completed on 20-21 days of the germination period in all cases.Analysis of variance showed the significance difference in germination success among the treatments but no significance difference in germination period among the treatment.Hot water treatment may be recommended on seed germination of the species in rural Bangladesh.
